Well, we(you all) have been through this process a few times in the past few years. It seems not to have brought in the new members or gotten people to show up in the past that you have wanted. I hesitate to post an opinion because I'm not a regular anymore. I mostly don't fly online anymore because I'm getting older(sleep/attention focus problems); and I'm doing other projects. But for me, my favorite part of flying online was flying actual simple missions. Something that was short and sweet and fun. Then, do it again, and again. The dogfight servers where everybody does whatever they want, I find boring. I can do that on my own.. ie:learning a DCS/Box plane. Once I can takeoff, nav, land and bomb/dogfight I would be ready to have fun online in a good mission. Or, if there was specific aircraft training, that I think is fun too. Touch and Gos, bombing range, all practicing a specific aircraft so we can fly that fun mission..
I will say that most of the successful online groups focus on 1 primary sim. Even in DCS that gives you ~30 complicated aircraft to fly? Even that is hard to get everyone to fly in a mission(ie. can't have a Spit on a mission with a F-18c). So, it's hard keep the old players and recruit new ones. So, I guess I agree with what Fen said in an above post. You need to pick 1-2 sims, state what day you fly them. Have regular "FUN" missions.
That's my 2 cents.